title: Brain and whole-body FDG-PET in diagnosis, treatment monitoring and long-term follow-up of primary CNS lymphoma.
abstract: BACKGROUND
  Positron emission tomography (PET) with F-18-labeled fluorodeoxyglucose (FDG) provides remarkable accuracy in detection, treatment monitoring and follow-up of systemic malignant lymphoma. Its value in the management of patients with primary central nervous system lymphoma (PCNSL) is less clear.
  
  
  METHODS
  In a prospective trial, 42 FDG-PET examinations were performed in ten immunocompetent patients with newly diagnosed or recurrent PCNSL before and repeatedly during and after the treatment. Brain and whole body FDG-PET were compared to brain MRI and extra-cerebral CT, respectively.
  
  
  RESULTS
  Before the treatment, 6 of 10 patients had congruent findings on FDG-PET and MRI of the brain. Three patients had lesions on brain MRI, not detected by FDG-PET. One patient had additional FDG-PET positive lesions inconspicuous in MRI. The follow-up suggested FDG-PET to be false positive in these lesions. After the treatment, brain PET was in agreement with MRI in 6 of 8 patients. In the remaining 2 patients there were persistent lesions in brain MRI whereas FDG-uptake was reduced to normal values. In the long-term follow-up of 5 patients (63-169 weeks), 3 patients retained normal in both PET and MRI. In 2 patients a new focal pathologic FDG-uptake was detected 69 and 52 weeks after the end of the treatment. In one of these patients, recurrence was confirmed by MRI not until 9 weeks after PET.
  
  
  CONCLUSIONS
  Brain FDG-PET may contribute valuable information for the management of PCNSL, particularly in the assessment of the treatment response. Integration of FDG-PET into prospective interventional trials is warranted to investigate prognostic and therapeutic implications.
authors.affiliation: Department of Nuclear Medicine, Vivantes MVZ Spandau, Berlin, Germany.
authors.forename: Sofiane
authors.initials: S
authors.lastname: Maza
authors.forename: Ralph
authors.initials: R
authors.lastname: Buchert
authors.forename: Winfried
authors.initials: W
authors.lastname: Brenner
authors.forename: Dieter Ludwig
authors.initials: DL
authors.lastname: Munz
authors.forename: Eckhard
authors.initials: E
authors.lastname: Thiel
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Korfel
authors.forename: Philipp
authors.initials: P
authors.lastname: Kiewe
keywords: PET-CT; imaging; primary central nervous system lymphoma; response assessment